Printed circuit cards support elements of electronic circuitry in various types of electrical equipment. For instance, circuit cards in a personal computer support a number of integrated circuits. The integrated circuits supported upon one circuit card send data comprising binary words to the integrated circuits of another circuit card through a data bus comprising an electrical backplane. The electrical backplane physically and electrically connects the integrated circuits of one circuit card with the integrated circuits of another circuit card.
FIG. 1 shows a prior art electrical backplane 10 connecting integrated circuits 11 of one circuit card 12 with the integrated circuits 13 of another circuit card 14. Each integrated circuit 11 or 13 has multiple terminal pins 15 or 16 that are connected to an edge connector 17 o 18 by a corresponding number of electrical conductors 19 or 20, for instance. The electrical conductors 19 or 20 comprise conductive traces that have been deposited on the circuit card 12 or 14, for instance. The electrical conductors 19 or 20 carry bits of a binary word in parallel from the terminal pins 15 of one integrated circuit 11 to the edge connector 17 mounted on the edge of the circuit card 12. The edge connector 17 mates with an electrical backplane connector 21. The electrical backplane connector 21, or 22, and wires or conductive traces on the backplane 10 comprises an electrical backplane such as a VME bus (IEEE P1014/D1), which carries the binary word from the edge connector 17 of the circuit card 12 to edge connectors, such as 18, of other circuit cards, such as 14. FIG. 1 only shows the interconnection between a pair of such circuit cards 12 and 14 for clarity. Electrical conductors deposited on other such circuit cards carry the binary bits from each edge connector to other integrated circuits on other circuit cards.
The terminal pins 15 of each integrated circuit 11 are typically connected such that the 1st, 2nd, . . . and nth terminal pins of one integrated circuit 11 electrically connect to the 1st, 2nd, . . . and nth terminal pins of another integrated circuit. Thus, when one integrated circuit 11 produces a binary word having a low bit at the 2nd terminal pin, for instance, the voltage of the 2nd terminal pin of each electrically connected integrated circuit 11 on circuit card 12 is pulled low and a low bit appears at the 2nd terminal pin of each integrated circuit. The binary word represents data, an address, or a control command sent to or from each integrated circuit.
The electrical connection between each edge connector 17 or 18 and the electrical backplane connector 10 can be misaligned during assembly of electrical equipment. The electrical connection between each edge connector 17 or 18 and the electrical backplane connector 10 can also loosen when electrical equipment is frequently moved. Misaligned or loose electrical connections result in short or open circuits and, thus, ineffective equipment.
A need exists for an apparatus that interconnects integrated circuits of different circuit cards and minimizes misalignment and the likelihood of faulty connections between such circuits.